Greenland - What Do We Know, What Is The Long Term Future And Is There Any Evidence Of A Melt Out?

[knocker]

Phoenix Glacier relic ice

 

I’m in South Greenland drilling low tech metal pipes into the ice to calibrate high tech satellite, aircraft, and model data.

 

Flying over this landscape, it’s stunning how much the ice has retreated. Annual (let alone summer) average air temperatures at nearby Narsarsuaq have been above the melting point 39 of the past 51 years [1]. Unequivocal evidence of rapid ice retreat; relic stranded ice [2] was what led Denmark to support scientists at GEUS to install modern ice monitoring measurements in 2001. The observations are now called “Q transect†as part of the PROMICE network around Greenland.

 

I was stunned to witness (and photograph) more stranded relic ice on the sides of the glacier. Notice how no ice is feeding Phoenix’s wings from upstream.

 

http://www.meltfactor.org/blog/?p=1293

Edited October 3, 2013 by knocker

[Fergus Brown]

Citation: Barletta, V. R., Sørensen, L. S., and Forsberg, R.: Scatter of mass changes estimates at basin scale for Greenland and Antarctica, The Cryosphere, 7, 1411-1432, doi:10.5194/tc-7-1411-2013, 2013. link here:http://www.the-cryosphere.net/7/1411/2013/tc-7-1411-2013.pdf

 

The summary conclusion:

 

For the whole GRACE period (2003–2011) our trend estimate for Greenland is −234 ± 20 Gt yr^−1 and −83 ± 36 Gt yr^−1 for Antarctica (−111 ± 15 Gt yr^−1 in the western part). We also find a clear (with respect to our errors) increase of mass loss in the last four years.

 

[Fergus Brown]

Spent some time looking at the available material. 

 

Questions: What is 'long-term'?

                   What do you mean by 'melt out'?

 

These matter because some of the material points to, for example, a total irreversible loss of the GIS over millennia if mean surface temperature over Greenland is anything betweeon 1-2c above pre-industrial levels.

 

Or are we looking at decades rather than centuries? And what proportion of the GIS would have to be 'lost' for it to count as 'melt out'? 

[Fergus Brown]

Read chapter 4 or chapter 13 of the AR5. - I have read the latter.

 

A 'inevitable' Greenland melt out is 'likely' to be locked in if temperature rises by 2 degrees. One study suggest the inevitable loss of the GIS might kick in for temperature increase of only one degree above pre-industrial. Possible it may not be so until temps are +4c.

 

Timescale - thousand years or more.

 

Solution? Radical mitigation reduces the rate of decline, permits the possibility of regrowth in the long term (post 2300, for example) to up to 80% of original levels.

 

Contribution to sea level rise? 1-3 metres by 2300, up to 5 metres longer scale, theoretical maximum 7 metres.

 

Sorry to be a stormcrow...

[be cause]

Phoenix Glacier relic ice

 

I’m in South Greenland drilling low tech metal pipes into the ice to calibrate high tech satellite, aircraft, and model data.

 

Flying over this landscape, it’s stunning how much the ice has retreated. Annual (let alone summer) average air temperatures at nearby Narsarsuaq have been above the melting point 39 of the past 51 years [1]. Unequivocal evidence of rapid ice retreat; relic stranded ice [2] was what led Denmark to support scientists at GEUS to install modern ice monitoring measurements in 2001. The observations are now called “Q transect†as part of the PROMICE network around Greenland.

 

I was stunned to witness (and photograph) more stranded relic ice on the sides of the glacier. Notice how no ice is feeding Phoenix’s wings from upstream.

 

http://www.meltfactor.org/blog/?p=1293

 

 

 Delighted to see you are getting out and about  !

[knocker]

Be interesting to read the first results on the Dark Snow project.

 

Black Carbon: Golden Opportunity?

http://ensia.com/features/black-carbon-golden-opportunity/

[knocker]

A theoretical basis how water can govern much of Greenland ice discharge rates

 

Greenland Ice Sheet Mass Balance Reconstruction. Part III: Marine Ice Loss and Total Mass Balance

Greenland ice sheet mass loss to the marine environment occurs by some combination of iceberg calving and underwater melting (referred to here as marine ice loss, L_M). This study quantifies the relation between L_M and meltwater runoff (R) at the ice sheet scale. A theoretical basis is presented explaining how variability in R can be expected to govern much of the L_M variability over annual to decadal time scales. It is found that R enhances L_M through three processes: 1) increased glacier discharge by ice warming–softening and basal lubrication–sliding; 2) increased calving susceptibility through undercutting glacier front geometry and reducing ice integrity; and 3) increased underwater melting from forcing marine convection. Applying a semiempirical L_M f(R) parameterization to a surface mass balance reconstruction enables total ice sheet mass budget closure over the 1840–2010 period. The estimated cumulative 171-yr net ice sheet sea level contribution is 25 ± 10 mm, the rise punctuated by periods of ice sheet net mass gain (sea level drawdown) (1893–1900, 1938–47, and 1972–98). The sea level contribution accelerated at 27.6 mm yr^−1 century^−1 over the entire reconstruction, reaching a peak sea level rise contribution of 6.1 mm decade^−1 during 2002–10.

 

 

http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-12-00546.1

[knocker]

The highest Greenland ice melt rates in 2013 occurred on July 25 when the ice sheet surface lost a total of 12 Gt

 

http://polarportal.dk/en/greenland-ice-shelf/rapporter/072013/

[knocker]

2013 Greenland melt summary just out

 

http://polarportal.dk/fileadmin/Images/polarportal/saesonrapporter/2013/Polar-portal-season-report-EN-2013.pdf

[knocker]

Greenland’s shrunken ice sheet: We’ve been here before

 

Clues in the Arctic fossil record suggest that 3-5,000 years ago, the ice sheet was the smallest it has been in the past 10,000 years

 

http://www.buffalo.edu/news/releases/2013/11/033.html

[Gray-Wolf]

So, if I'm understanding this correctly, it would appear that ice sheet degradation relies upon sea temps and not air temps ( which is why the sheet did not respond as strongly to the atmospheric thermal max as the oceanic' peak'?). Post ice age meltdown the oceans would have been impacted with a lot of cold melt waters and spent a long time rebuilding global ocean temps to the point that they could then 'warm' to the point the point that drove the ice sheet reduction?

 

Todays 'warming oceans' do not have to fight the impacts of the end of an ice age and so you would expect any warming to be far faster? Recent warming appears to confirm that and does not instill me with confidence about the future?

 

We have known for over a decade of the warm Atlantic waters eating into the East Greenland glaciers ( and impacting the Baffin/Nares west coast of Greenland) and for over 5 years of the ingress of warmer Southern ocean waters around the Antarctic Continent. How long will it take the recent warming spurt in the oceans to present itself at the grounding line of the glaciers/ice shelves of the planet and how warm do we expect our oceans to become under AGW drivers?

[Gray-Wolf]

http://www.nature.com/nature/journal/v504/n7478/full/nature12854.html?

 

Not good reading. Not deniable reading though?

[knocker]

Quite agree GW. I rather like this photo.

 

Calving Greenland glacier courtesy Sarah Das â€@sarahbdas

 

 

Edited December 5, 2013 by knocker

[Gray-Wolf]

http://www.bbc.co.uk/news/science-environment-25463647?

 

I'm sure we heard of this back when the 'discovery' was made but now we seem to have more data as the paper has been released. I seem to recall asking if anyone knew whether this extra 'loading' could have consequences on physical collapse/slumping of sections of the ice sheet?

 

It appears they were back ( and better equipped to measure this time!) in April so it would be interesting to see what 2012's exceptional melt season across Greenland has done to the melt water?

[knocker]

The paper.

 

Extensive liquid meltwater storage in firn within the Greenland ice sheet

 

Mass loss from the Greenland ice sheet contributes significantly to present sea level rise¹. High meltwater runoff is responsible for half of Greenland’s mass loss². Surface melt has been spreading and intensifying in Greenland, with the highest ever surface area melt and runoff recorded in 2012³. However, how surface melt water reaches the ocean, and how fast it does so, is poorly understood. Firn—partially compacted snow from previous years—potentially has the capacity to store significant amounts of melt water in liquid or frozen form⁴, and thus delay its contribution to sea level. Here we present direct observations from ground and airborne radar, as well as ice cores, of liquid water within firn in the southern Greenland ice sheet. We find a substantial amount of water in this firn aquifer that persists throughout the winter, when snow accumulation and melt rates are high. This represents a previously unknown storage mode for water within the ice sheet. We estimate, using a regional climate model, aquifer area at about 70,000 km² and the depth to the top of the water table as 5–50 m. The perennial firn aquifer could be important for estimates of ice sheet mass and energy budget.

 

http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo2043.html

[Gray-Wolf]

I've read that 2 more 'big melt' years could prove too much for the saturated layer leading to a sudden release event? I wonder just what impact this would have on the surface topography of the area underlain by the super saturated firn and whether this itself holds implication for melt in the area?

[knocker]

Many outlet glaciers in Greenland feed ice from the land into fjords, where discharge of icebergs and melting of the glaciers by warmer ocean waters contribute to rising sea levels. David Holland of NYU studies what happens in the fjord when ice meets water – how the dynamics at the margin between ice and sea are changing, and what those changes could mean in the future for global sea level rise.In recent years, the rate of ice flow from the land to the water has accelerated in some glaciers, and the melting of the ice in the fjords has also increased. The purpose of this project is to improve the understanding of the role of the ocean in these fast, dynamical changes at the margin of the Greenland Ice Sheet.The glaciers feeding into two fjords, Jakobshavn on the west coast and Helheim on the east coast, have accelerated significantly in recent years. Holland and his team have been making oceanographic and meteorological observations in these fjords. These observations are being used to develop and validate a coupled model of the ocean and ice sheet that will enable improved understanding of processes that contribute to sea level rise.

Provided by the National Science Foundation

 

 

 

http://science360.gov/obj/video/9b9b8bb3-6f48-4ef9-be0b-7516a91d4675/mathematician-uses-skills-study-greenlands-retreating-glaciers

[knocker]

Dark Snow Project First Science Results

[knocker]

An article on Jason Box and the Dark Snow project.. A scientist not afraid to get out there at the coal face. So to speak.

 

A darker shade of snow

 

http://www.boulderweekly.com/article-12164-a-darker-shade-of-snow.html

Edited January 10, 2014 by knocker

[knocker]

Koge Bugt Outlet Glacier, Southeast Greenland

 

Koge Bugt Glacier is an outlet of the Greenland Ice Sheet on the southeast Coast. The glacier empties into the bay of the same name, and has three main calving fronts. This glacier is the the sweet spot for high snowfall and hence, despite its smaller size is one of the larger outlet glaciers in terms of volume.

 

http://glacierchange.wordpress.com/2014/01/21/koge-bugt-outlet-glacier-southeast-greenland/?utm_source=dlvr.it&utm_medium=twitter

[knocker]

Jason Box

 

new chapter for textbooks; video showing our surprise discovery: liquid water in Greenland snow http://www.youtube.com/watch?v=7VEpJpCvrbI&feature=youtu.be â€¦ a "perenial aquifer"

[Gray-Wolf]

To me the issue is one of 'over-saturation'?

 

When this occurs you lose a huge swathe of cover is lost as gravity takes charge and it slips down-slope. This reveals the ice below which is a lower albedo than the pristine snow cover above leading to more melt and ingress into the ice sheet itself?

[knocker]

Greenland's fastest glacier reaches record speeds

 

Jakobshavn Isbræ (Jakobshavn Glacier) is moving ice from the Greenland ice sheet into the ocean at a speed that appears to be the fastest ever recorded. Researchers measured the dramatic speeds of the fast-flowing glacier in 2012 and 2013.

 

http://www.sciencedaily.com/releases/2014/02/140203101016.htm

[knocker]

A Look Back and Ahead at Greenland's Changing Climate

 

Over the past two decades, ice loss from the Greenland Ice Sheet increased four-fold contributing to one-quarter of global sea level rise. However, the chain of events and physical processes that contributed to it has remained elusive. One likely trigger for the speed up and retreat of glaciers that contributed to this ice loss is ocean warming.

 

A review paper by physical oceanographers Fiamma Straneo at Woods Hole Oceanographic Institution (WHOI) and Patrick Heimbach at MIT published in Nature explains what scientists have learned from their research on and around Greenland over the past 20 years and describes the measurements and technology needed to continue to move the science forward.

 

http://www.whoi.edu/news-release/Greenland-Research-Overview

[4wd]

http://dailycaller.com/2013/12/18/vikings-could-navigate-colonize-the-arctic-during-medieval-times/#ixzz2sZZYYuko 

 

 

According to an 1887 newspaper article entitled “Variations in Climate,†Scandinavian Vikings were able to sail through the Arctic Ocean and establish colonies in the “highest north latitude†of Greenland and North America centuries before the arrival of Christopher Columbus. These colonies, however, were abandoned by the Vikings due to “the increasing cold.â€

Read more: http://dailycaller.com/2013/12/18/vikings-could-navigate-colonize-the-arctic-during-medieval-times/#ixzz2saQoaT9Z